Croagh Patrick in Co Mayo owes its existence to the Caledonian Orogeny
Remembering these, we will over the next few pages go over how the rocks and sediments of Cork City formed. This overview will not only give you an idea of how the area of Cork came to be, but will hopefully also make it easier to understand the geology of the sites described in this booklet. It starts rather dramatically with… The Caledonian Orogeny Somewhere between 500 and 450 million years ago, dramatic events started to unfold in the area north of what is now Cork. At the time, this area was part of the Iapetus Ocean. This ocean does not exist anymore, as it was literally pulled and pushed into the Earth through the dynamics of our moving continents. Since our landmasses and continents formed, they have always been on the move; their main movements being driven by their creation (through regions spreading) and destruction (through regions colliding); large-scale processes that we call ‘plate tectonics’. So, between 500 and 400 million years ago, two of these moving land masses collided. Slowly (on a human timescale), but still powerfully, these collisions pushed up a mountain chain. Geoscientists refer to this huge event as the Caledonian orogeny and the resulting chain of mountain as the Caledonides or Caledonian mountains. This mountain chain has largely been eroded today, but the leftovers of it appear as the hills of Donegal, Galway, Mayo (a stark example is Croagh Patrick visible in the picture above) and Sligo, the Scottish Highlands and the mountains of Norway. While “Cork City” was not a part of this huge mountain chain, it owes its existence to it, and that is why we cannot ignore these dramatic events. As mountains are created, they erode as well. Together, weather, gravity and water break down mountains. Large mountains shed a lot of sediments, and that is what happened back then.
08
Powered by FlippingBook